The present invention concerns a floating wind power apparatus with a floating unit and at least three rotors supported in rotor housings or nacelles. The rotor housings are placed on separate towers with a longitudinal central axes. The towers are attached to the floating unit and to the rotor housings. The floating unit can turn to direct the rotors in relation to the wind. At least one of the rotors is a downwind rotor, and at least one rotor is an upwind rotor. The towers are placed at an inclined angle in relation to the rotors. Rotor, turbine, propeller or mill is in this connection meant to describe that part of the apparatus that is put in rotation by the wind and that transfers the energy of the wind to mechanical energy.
When floating wind power generators are placed in bodies of water, there are a number of challenges in relation to anchoring, handling of big waves, ice, corrosion and maintenance. For such plants it is also a challenge to keep the plane of the rotors in a plane perpendicular in relation to the direction of the wind, in particular in the vertical plane, as the wind has a tendency to pivot the structure such that the rotors are inclined in relation to a vertical direction.
In EP 1 106 825 it is shown a floating plant with three wind turbines are placed on a floating platform. The turbines are placed on vertical towers and all the turbines are upwind turbines.
In NL 1008318C it is shown a floating wind turbine island with a number of upwind wind turbines placed on vertical towers at each corner of a floating unit.
In DE 102004049506 it is shown a wind power plant with a number of rotors placed on a pontoon. The rotors are mechanically connected to each other and drive a common generator.
However none of the publications show solutions with a combination of upwinds- and downwind rotors on separate, inclined towers such that an improved balance is achieved in combination with a reduced disturbance of the wind for the downwind rotor/rotors in the same way as in the present invention.
In connection with downwind rotors it is a problem that wind disturbances from the tower create disturbances on the rotor that can result in uneven load that may result in reduced efficiency, vibrations and fatigue fractures.
When floating wind turbines are placed separately in bodies of water, must each turbine be anchored, maintained, and export energy separately.